Effectively Using a Shallow Depth-of-Field

Today’s digital SLR cameras are extremely advanced in technology while being very user friendly. Today’s DSLRs are feature-rich and entry-level models are very well priced.

Unfortunately, when people purchase an entry-level model DSLR, they never seem to get beyond the automatic settings. Although today’s cameras are smart and you’ll almost certainly always get usable photos from the automatic settings, you may want a photograph to have a more polished, professional look.

I’m going to make a fairly safe assumption here and say that pros rarely, if ever, use the camera’s automatic setting. You won’t have to either with a little practice and soon you’ll be making better images than ever before.

I’ll be discussing the use of shutter speed, film speed and aperture values in great detail on this Website. For now, though, I just want to give you one little tip to help you make better images.

Depth-of-Field BasicsLet’s first examine the term depth-of-field. For the purpose of our discussion here, the depth-of-field is the measurement of how much of the background

A shallow depth-of-field causes the background to blur so the background doesn't compete with the subject. (Photo Credit: Jeremy W. Schneider)

is in focus behind the subject. For instance, this image has a relatively shallow depth-of-field because very little behind the subject is in focus:

Notice how the background is “fuzzy” and out of focus? That’s because I’m utilizing a shallow depth-of-field. Why? Because when I noticed the background, I saw that it was distracting. There were twigs, leaves, and some other unflattering objects in the background that I didn’t want in the image.

An unflattering background will absolutely KILL a great shot. A distracting background takes the viewers’ attention away from the subject.

Controlling Depth-of-Field
Depth-of-field is controlled by the lens’ aperture. Again, in future posts we’ll go into deeper detail about the aperture but for now, let’s just remember that it controls the depth-of-field.

Where to Begin
First, take your DSLR off the automatic setting and put it on the “Av” or “A” setting. This is the aperture control setting. In this mode, you control what aperture setting you want and the camera will calculate the corresponding shutter speed.

Now, the aperture settings are measured in units called “F-stops.” The numbers are generally written as “f/number” such as f/2.8 or f/4 or f/5.6. These units measure how large the aperture is opened, thus measuring how much light is allowed into the camera.

Here’s the little oddity about F-values: The smaller the number, the larger the aperture opening and vice versa. For example: f/2.8 has a larger opening than f/5.6.

The larger the opening, the shallower the depth-of-field. So, you would see more background in focus if the aperture setting is at f/8 than if the setting was at f/2.8.

Confused? Don’t be. Just remember this: The smaller the number, the less background that is in focus.

This image has a depth-of-field that allows the subjects - the two ATVs - to be in focus but starts to get less focused deeper into the image. (Photo Credit: Jeremy W. Schneider)

Now that you understand how this works, go out and try different F-values and experiment to see what results you get. I guarantee you’ll make better images by controlling the aperture value.